Physicians in the UK were unable to explain a strange ring-like pattern moving across a patient's brain tissue in a series of scans taken over four years. During a biopsy, they were shocked to learn it was a one centimeter-long parasitic tape worm. »11/21/14 7:20am 11/21/14 7:20am

A stickleback is heading for a warm bath. While its peers prefer to swim in lukewarm water at around 16 degrees Celsius, this individual likes it hotter. That's not because of a personal preference – instead, it is being steered by a parasite. A tapeworm has lodged in its guts, and it needs warmer temperatures to grow… »11/19/11 3:05pm 11/19/11 3:05pm